1. Technical Field
The present invention relates to a method and apparatus for generating data concerning partitions of land by analyzing an ground image photographed at high altitude by a high-altitude flying vehicle such as a satellite or an airplane.
2. Background Art
Satellite and aerial photography is becoming increasingly common. Various techniques are being developed for creating maps or analyzing the land surface, for example, based on images provided by the photography.
In particular, in order to analyze photographs of a farming area, a method is required for recognizing farmland partitions within an image.
A farmland partition is usually recognized by extracting from an image a polygon (to be hereafter referred to as a rectangle) enclosed by edges indicating farmland. As an example of the prior art for recognizing a rectangle in an image, JP Patent Publication (Unexamined Application) No. 11-266373 discloses an image processing apparatus. This apparatus employs an edge tracing technique in an edge-extracted and binarized image.
Further, JP Patent Application No. 6-146651 discloses an apparatus for rectangle processing in an intra-frame area. This apparatus employs a method whereby an area is designated by a marking pen or the like and then read as rectangle information.
The above-mentioned edge tracing technique for recognizing a rectangle area requires the user to judge as to the determination of the trace direction during the edge trace process. As a result, this technique is inevitably dialog-based, requiring much time and energy on the part of the user.
The other prior art technique, namely the designation of an area by a marker or the like, requires all of the areas needing recognition to be marked by the user in advance, thus also requiring the user to expend much energy.